The rapid development of the field of communication has entailed that the need for faster and more reliable transmission media has increased drastically. Optical fibres have revolutionized transmission possibilities. These fibres allow a large number of signals to be transferred in one and the same fibre and with speeds near that of light. Since the fibre length is limited at manufacture, these have to be connected by means of different connecting devices.
Connecting devices have to connect optical fibres with each other, so that the fibre ends are located exactly axially right in front of each other. A problem at connection of optical fibres end-ways with each other is their small diameter, that amounts to some or some tenths of millimeters, while its optical core can have a diameter of 10-50 .mu.m. A deviation of a thousandth part of a millimeters therefore constitutes a coarse deviation, whereby the transmission losses increase drastically. Therefore there are very great demands on the tolerances of the connecting device, which entails complicated designs and high manufacturing costs.
Through the swedish patent application 8903366-6, is known a connecting device for optical fibres, which device requires specially formed means to center optical fibres relatively each other.
Previously known are connecting devices according to the british patent GB-2002136, where a spherical lens is used for transfer of light signals, as well as U.S. Pat. Nos. 4,421,383, 4,691,985, 4,711,518 and 4, 770,488 for centering and connection of an optical fibre with a lens device. The lens devices in each connecting device are used to transmit the light between two fibre ends. In these documents there are no directions of how the centering of the glass fibre relatively the lens and the coupling house should be achieved.
Purpose and most essential features of the invention
The purpose of the invention is to achieve a connecting device for very thin optical fibres, which enables a very secure and exact centering and connection of the fibre ends, which makes it possible to connect fibres of different size and which counteracts deformations of the optical fibres at the connection. By means of the connecting device self-centering lenses are obtained, which are used for transmission of light signals between two fibre end portions. In addition the manufacture of the connecting device shall be simple and cheap. These tasks have been solved by each lens being constituted by a lens body, the front end surface of which is partial spherical and the opposite rear end surface of which is arranged perpendicular against the longitudinal axis of the lens body, that in the coupling house is provided a ring shaped, partial spherical or conical seat for the front end surface of the lens body, which seat is concentric with the longitudinal axis of the coupling house, that the plug is insertable in a coaxial guide sleeve guided in the coupling house, and that the front end of the plug, which is perpendicular versus its longitudinal axis, can be pressed to bearing against the rear end surface of the lens body so that the front, partial spherical end surface of the lens body is pressed to bearing against the seat achieving a centering of the lens body, the plug and the coupling house relatively each other.